docs: def _replace_with_specific_page(page, menu_item):
          """
          If ``page`` is a vanilla ``Page` object, replace it with a 'specific'
          version of itself. Also update ``menu_item``, depending on whether it's
          a ``MenuItem`` object or a ``Page`` object.
          """
          if type(page) is Page:
              page = page.specific
              if isinstance(menu_item, MenuItem):
                  menu_item.link_page = page
              else:
                  menu_item = page
          return page, menu_item